Passenger transportation system and relative control method

ABSTRACT

A passenger transportation system having at least one rail extending along a path; at least one trolley movable along the rail; an actuating device having a linear electric motor, in turn having at least one slide fitted to the trolley, and a linear stator extending at least partly along the path, and having an elongated body, and a quantity of power windings embedded in the elongated body; and a quantity of sensors configured to control the position of the trolley, the sensors being fitted to the elongated body and so positioned as to minimize noise generated by the power windings on the sensors.

PRIORITY CLAIM

This application is a continuation of, claims the benefit of andpriority to U.S. patent application Ser. No. 13/518,279, filed on Oct.12, 2012, which is a national stage application of PCT/IB2010/003328,filed on Dec. 22, 2010, which claims the benefit of and priority toItalian Patent Application No. MI2009A 002273, filed on Dec. 23, 2009,the entire contents of which are each incorporated by reference herein.

BACKGROUND

In certain transportation systems comprising a linear electric motor,the position of the slide is normally determined by proximity sensors,such as described in PCT Patent Application WO 2009/019259.

Correct operation of the transportation system therefore dependsdirectly on the sensors, and in particular the location of the sensors.

Known transportation systems are normally installed by first installingthe structural components, and then the control components.

If the sensors are located wrongly during installation of the system(e.g., in the wrong position, such as too close, or too far away) withrespect to the rail, and therefore with respect to the slide transitarea, this could result in malfunctioning of the system, with all theassembly or repair cost and time this entails.

SUMMARY

In various embodiments, the present disclosure relates to a passengertransportation system and relative control method.

More specifically, one embodiment of the present disclosure relates to atransportation system comprising:

at least one rail extending along a path;

at least one trolley movable along the rail; and

an actuating device comprising a linear electric motor, in turncomprising at least one slide fitted to the trolley, and a linear statorextending at least partly along the path, and comprising an elongatedbody, and a quantity of power windings embedded in the elongated body.

The slide is moved by a magnetic field generated by the linear stator,and is controlled by the magnetic field as a function of the position orspeed of the slide.

It is an advantage of the present disclosure to provide a transportationsystem configured to eliminate certain of the drawbacks of knowntransportation systems, and in particular to provide a transportationsystem which can be installed cheaply and easily.

Another advantage of the present disclosure is to provide atransportation system that is less susceptible to installation defects.

According to one embodiment of the present disclosure, there is provideda passenger transportation system comprising:

at least one rail extending along a path;

at least one trolley movable along the rail;

an actuating device comprising a linear electric motor, in turncomprising at least one slide fitted to the trolley, and a linear statorextending at least partly along the path, and comprising an elongatedbody, and a quantity or number of power windings embedded in theelongated body; and a quantity or number of sensors configured tocontrol the position of the trolley; the sensors being fitted to theelongated body and so positioned as to minimize noise generated by thepower windings on the sensors.

In one embodiment of the present disclosure, the sensors can be fittedaccurately to the elongated body at the production plant, beforeinstalling the system, thus avoiding any problems posed by improperassembly of the sensors at the installation stage.

In one embodiment, the sensors are embedded in the elongated body.

In one embodiment of the present disclosure, the sensors are removablyinstalled in a designated position to ensure correct operation of thetransportation system.

In another embodiment, the power winding generates a first magneticfield by passage of current in the power winding; the slide includes asecond magnetic field generator which generates a second magnetic fieldwhich interacts with the first magnetic field and moves the slide alongthe path; the sensor comprising a control winding; and the secondmagnetic field travels through the control winding when the slidetravels close to the control winding; the control winding generatingcurrent by interaction with the second magnetic field.

In one embodiment of the present disclosure, the control windingeffectively determines passage of the slide in a relatively simple,functional, low-cost manner, and needs no power, by virtue of passage ofthe slide being determined by interaction of the second magnetic fieldon the control winding; which interaction generates a detection signalon the control winding—in the example shown, in the form of a voltage orelectric current generated by linkage of the second magnetic field withthe control winding.

Another advantage of the present disclosure is to provide a method ofcontrolling a transportation system configured to eliminate certain ofthe drawbacks of known transportation systems.

Another advantage of the present disclosure is to provide a relativelysimple, effective method of controlling a transportation system.

According to one embodiment of the present disclosure, there is provideda transportation system control method; the transportation systemcomprising an actuating device in turn comprising a linear electricmotor, which comprises at least one slide and a linear stator extendingat least partly along a path and in turn comprising at least one powerwinding; and at least one control winding; the slide and the linearstator being magnetically connectable to induce movement of the slidealong the path; and the method comprising the steps of the controlwindings detecting a transit signal, and determining a position or speedof the slide as a function of the transit signal.

Additional features and advantages are described in, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present disclosure will be described byway of example with reference to the accompanying drawings, in which:

FIG. 1 shows a partly sectioned plan view, with parts removed forclarity, of a cable transportation system equipped with a linearelectric motor;

FIG. 2 shows a larger-scale, partly sectioned front view, with partsremoved for clarity, of a detail of the FIG. 1 cable transportationsystem;

FIG. 3 shows a partly sectioned view in perspective, with parts removedfor clarity, of a detail of the linear electric motor of the FIG. 1cable transportation system;

FIG. 4 shows a schematic exploded view in perspective, with partsremoved for clarity, of a detail of the linear electric motor in FIG. 3;

FIG. 5 shows a larger-scale, partly sectioned plan view, with partsremoved for clarity, of the detail of the linear electric motor in FIG.1;

FIG. 6 shows a partly exploded, partly sectioned view in perspective,with parts removed for clarity, of a detail of the linear electric motorin FIG. 1; and

FIG. 7 shows a schematic of a detail of the linear electric motor inFIG. 1, and a relative control unit.

DETAILED DESCRIPTION

Referring now to the example embodiments of the present disclosureillustrated in FIGS. 1 to 7, number 1 in FIG. 1 indicates a passengertransportation system. In the FIG. 1 example, transportation system 1 isa cable transportation system, and comprises a looped draw cable 2; anda quantity or number of transportation units 3 of the type suspendablefrom draw cable 2—such chairs of a chairlift or cars of a cable-carsystem—and movable along a given or designated path P1.

Transportation system 1 comprises a passenger station 4; and anactuating device in turn comprising a linear electric motor 5 configuredto drive transportation units 3 into passenger station 4.

Linear electric motor 5 is located partly in transportation units 3 andpartly in passenger station 4.

Passenger station 4, which in the example shown is a turnaround station,comprises a pulley 6, about which draw cable 2 is looped; a control unit7; and a frame 8 supporting transportation units 3 in passenger station4.

Frame 8 extends along a portion of path P1, and comprises a beam 9which, viewed from above, is U-shaped, and supports a quantity or numberof supporting structures 10.

Linear electric motor 5 comprises a linear stator 11, which extendsalong path P1, is supported by beam 9, and, viewed from above, isU-shaped.

With reference to FIG. 2, each supporting structure 10 supports threerails 12, 13, 14; and each transportation unit 3 comprises a suspensionarm 15, and a trolley 16 which engages rails 12, 13, 14 at station 4.

Trolley 16 comprises a coupling device 17 configured to selectivelyconnect trolley 16 and transportation unit 3 to draw cable 2, and which,in FIG. 2, is shown releasing draw cable 2.

Trolley 16 has three rollers 18, 19, 20, which engage respective rails12, 14, 13 to define a given or designated position of trolley 16.Accordingly, rail 12 has a C-shaped cross section, and respective roller18 engages the C-section rail 12.

For each transportation unit 3, linear electric motor 5 comprises aslide 21 integral with trolley 16, and which cooperates with linearstator 11 to move respective transportation unit 3 inside passengerstation 4. In the example shown, slide 21 is connected to trolley 16 andsuspension arm 15 by a bracket 22.

Each transportation unit 3 travelling through passenger station 4 ismoved by respective slide 21, which couples with linear stator 11 oflinear electric motor 5, which, together with rails 12, 13, 14, definesan auxiliary actuating device of transportation system 1.

With reference to FIG. 5, linear stator 11 comprises an elongated body23 (FIG. 3) of nonferrous material—in the example shown,glass-fibre-reinforced epoxy resin; a quantity or number of powerwindings 24 embedded in elongated body 23, and which generate a firstmagnetic field by passage of electric current in power windings 24; anda quantity of sensors 25 fitted to elongated body 23, and configured tocontrol the position of trolley 16.

In the FIG. 3 example, linear stator 11 comprises brackets 26 configuredto fix elongated body 23 to beam 9 (FIG. 1).

Sensors 25 are arranged with respect to power windings 24 to minimizethe noise generated by power windings 24 on sensors 25, and, inparticular, are embedded in elongated body 23.

Slide 21 comprises a second magnetic field generator which generates asecond magnetic field, which interacts with the first magnetic field andmoves slide 21 along path P1.

With reference to FIG. 7, elongated body 23 comprises a quantity ornumber of modular units 27 aligned along path P1.

With reference to FIG. 3, each modular unit 27 extends along an axis ofsymmetry A, and is in the form of a flat plate to define a straightportion of path P1. In another embodiment (not shown in the drawings),each modular unit is in the form of a curved plate to define a curvedportion of path P1.

Each modular unit 27 has a rectangular cross section; two opposite,parallel main faces 28 positioned substantially horizontally; twolateral faces 29; and two end faces 30.

With reference to FIG. 7, each modular unit 27 comprises a given ordesignated quantity of said quantity of power windings 24. Morespecifically, each modular unit 27 comprises three power windings 24arranged in succession and associated with respective phases R, S and T.

With reference to FIG. 5, each modular unit 27 comprises a quantity ornumber of power connection elements 31 configured to connect thedesignated quantity of power windings 24 to the designated quantity ofpower windings 24 of an adjacent modular unit 27, and each of which isparallel to axis of symmetry A. More specifically, each modular unit 27comprises six power connection elements 31 located along end faces 30,and which, in the example shown, comprise three male connection elementsand three female connection elements, are divided between the two endfaces 30, and are symmetric with respect to axis of symmetry A.

Each modular unit 27 comprises a designated quantity of sensors 25; anda quantity of control connection elements 32 configured to controlsensors 25 and connecting the given or designated quantity of sensors 25of modular unit 27 to the given or designated quantity of sensors 25 ofan adjacent modular unit 27. More specifically, each modular unit 27comprises three sensors 25; and, in one embodiment, control connectionelements 32 are located along end faces 30 and divided equally betweenmale control connection elements and female control connection elements.

In one embodiment, each modular unit 27 comprises twelve controlconnection elements 32, so they can be arranged symmetrically withrespect to axis of symmetry A along each end face 30. Though six controlconnection elements 32 would be enough to connect sensors 25 of modularunits 27, the control connection elements 32 along each end face 30 are,in at least one embodiment, doubled so they can be arrangedsymmetrically along end faces 30.

With reference to FIG. 6, power winding 24 comprises a conductor 33,such as a flat conductor perpendicular to main faces 28.

With reference to FIG. 4, power winding 24 is wound in a direction V1about an axis A1 to form a coil 34 comprising a quantity or number ofturns, and in a direction V2, opposite V1, about an axis A2 to form acoil 35 comprising a quantity or number of turns. For the sake ofsimplicity, only a few of the turns of power winding 24 are shown. Eachcoil 34, 35 comprises two groups of turns wound in the same direction;and the two groups lie in separate planes, are parallel to each otherand to main faces 28 (FIG. 3), and form a gap between the two planes.

In an alternative embodiment (not shown in the drawings), power winding24 comprises a one-turn coil 34, and a one-turn coil 35.

In one embodiment of the present disclosure, coils 34 and 35 of powerwinding 24 each have twenty-four or forty-eight turns and are connectedto each other.

With reference to FIG. 6, each sensor 25 comprises a control winding 36embedded in the non-ferrous material of elongated body 23, andconfigured to detect passage of slide 21 (as seen in FIG. 3). In otherwords, each sensor 25 is substantially defined by control winding 36itself. When slide 21 passes close to control winding 36, the secondmagnetic field generated by slide 21 (as seen in FIG. 7) links withcontrol winding 36, which is configured to generate electric currentfrom the interaction with the second magnetic field.

With reference to FIG. 4, control winding 36 has a plane of symmetry Uequidistant from axis A1 and axis A2.

With reference to FIG. 7, each modular unit 27 comprises three controlwindings 36, which are associated with the three power windings 24 ofthe same modular unit 27, are arranged in succession, and are thereforeassociated with respective phases R′, S′, T′ coupled with respectivephases R, S, T.

In one embodiment, linear stator 11 is divided into modular sections 37,each comprising a quantity of modular units 27. The power windings 24 ofthe same modular section 37 and associated with the same phase R, S, Tare connected in series with one another by power connection elements31, and define respective groups of power windings 24. Similarly, thecontrol windings 36 of the same modular section 37 and associated withthe same phase R′, S′, T′ are connected in series with one another bycontrol connection elements 32, and define respective groups of controlwindings 36. Both power- and control-wise, each modular section 37 isisolated electrically from the other modular sections 37 by isolatingelements 38, and has connectors (not shown) configured to connect powerwindings 24 and sensors 25 to a power assembly 39 configured to powerpower windings 24, and which is adjustable in voltage, current,frequency, and phase, and, in the example shown, comprises an inverter.

Sensors 25 of each section are connected to a control unit 40, whichcontrols power assembly 39.

Power connection elements 31 and control connection elements 32 aresymmetrical with respect to axis of symmetry A, so two modular units 27can be connected to form a succession of power phases R, S, T, R, S, Tand a succession of control phases R′, S′, T′, R′, S′, T′, or asuccession of power phases R, S, T, T, S, R and a succession of controlphases R′, S′, T′, T′, S′, R′, by simply turning one of the two modularunits 27 over about axis of symmetry A.

With reference to FIG. 1, in addition to linear electric motor 5, theactuating device comprises control unit 40, which is connected tocontrol unit 7 of transportation system 1; and a quantity of powerassemblies 39 equal to the quantity of modular sections 37 of linearstator 11. An alternative embodiment (not shown in the drawings),includes one power assembly for all the sections, and comprises aquantity of independently adjustable three-phase outputs, equal to thequantity of modular sections.

With reference to FIG. 1, each power assembly 39 is connected torespective power windings 24 and to control unit 40, and comprises threeoutput terminals, each associated with one of phases R, S, T, so eachgroup of power windings 24 is powered with the same frequency F, thesame current intensity I, and one of phases R, S, T.

With reference to FIG. 3, each slide 21 comprises a U-shaped plate 41with two opposite parallel faces 42, along which are fitted two sets ofpermanent magnets 43.

The two sets of permanent magnets 43 are arranged opposite each otherand far enough apart to fit slide 21 about linear stator 11. That is,each set of permanent magnets 43 is substantially parallel to and facesa main face 28 of elongated body 23, so as to form a gap betweenpermanent magnets 43 and respective main face 28.

With reference to FIG. 5, control windings 36 are equally spaced alongpath P1, and detect passage of transportation units 3 (as seen inFIG. 1) along path P1.

With reference to FIG. 7, control unit 40 acquires transit signals STR,STS, STT; calculates speed signals SV related to speeds V, and positionsignals SP related to positions P of slide 21; and compares speedsignals SV with a target speed signal SVD related to a target speed VD.

With reference to FIG. 4, control winding 36 is positioned so that themagnetic flux from power winding 24 linked to it is substantially nil.In other words, control winding 36 is so located inside linear stator 11that, when power winding 24 is powered, the positive magnetic fluxgenerated by coil 34 or 35 through the inner surface defined by controlwinding 36 substantially equals the negative magnetic flux generated bycoil 35 or 34 through the inner surface defined by control winding 36.The total flux through the inner surface defined by control winding 36is thus substantially zero, and so induces no voltage at the terminalsof control winding 36.

Each control winding 36 is configured to detect passage of slide 21.That is, the variation in magnetic flux produced by passage of slide 21induces, at the terminals of control winding 36, a voltage whichproduces transit signal STR, STS or STT.

The control windings 36 associated with the same phase R′, S′, T′ andthe same modular section 37 of linear stator 11 are connected in series,and define respective (i.e., three), groups of control windings 36: oneassociated with phase R′, one with phase S′, and one with phase T′.

Three transit signals STR, STS, STT, emitted by respective groups ofcontrol winding 36 and connected to control unit 40, are thereforedefined for each modular section 37.

With reference to FIG. 7, control unit 40 comprises a processing block44 configured to process transit signals STR, STS and STT, and calculatespeed signal SV and position signal SP.

Processing block 44 is also configured to condition transit signals STR,STS, STT according to the speed signals SV of slide 21 calculated theinstant before.

To calculate speed signal SV, processing block 44 processes the transitsignals STR, STS, STT from respective phases R′, S′, T′ to change fromstationary coordinates to two movable coordinates: a direct coordinate,and a quadrature coordinate perpendicular to the direct coordinate. Morespecifically, processing block 44 applies first a Clarke and then a Parktransform to transit signals STR, STS, STT to define a quadrature signalrepresenting the quadrature component of the movable-coordinate systemof transit signals STR, STS, STT. Speed signal SV is calculated as afunction of the quadrature signal of transit signals STR, STS, STT, andmore specifically is defined by the output of a proportional-integralblock whose input is the quadrature signal.

Processing block 44 calculates position signal SP on the basis of speedsignal SV.

Control unit 40 comprises a regulating block 45, which, for each modularsection 37, defines regulating signals SR for a respective powerassembly 39 as a function of position signal SP, speed signal SV, targetspeed signal SVD, and a target position signal SPD. On the basis ofregulating signal SR, power assembly 39 regulates the intensity I,frequency F, and phases R, S, T of the electric current of the groups ofpower windings 24 to achieve a speed V of slide 21 as close as possibleto target speed VD.

Linear electric motor 5 is also configured to move transportation units3 (as seen in FIG. 1) along path P1 in the opposite to normal travellingdirection. This is achieved by inverting the phase sequence, and isuseful for equally spacing transportation units 3.

With reference to FIG. 7, control unit 40 comprises a reference winding46 and a compensating block 47, which compensate for any electromagneticnoise that might deteriorate each transit signal STR, STS, STT acquiredby each control winding 36.

Reference winding 46 is located to acquire a noise signal SD indicatingthe electromagnetic fields of any electromagnetic noise on controlwinding 36. To do this, reference winding 46 is located far enough awayfrom slide 21 and power windings 24 to avoid picking up the magneticfields produced by them.

Compensating block 47 receives the transit signals STR, STS, STTassociated with respective control windings 36, and noise signal SD fromreference winding 46, and processes transit signals STR, STS, STT as afunction of noise signal SD, to compensate for any noise.

In an alternative embodiment, reference winding 46 is eliminated, andcompensating block 47 receives noise signal SD from a control winding 36of a modular section 37 other than the one associated at the time withthe transit signals STR, STS, STT being noise-corrected. Morespecifically, the modular section 37 must be chosen from those notsupplied with current at the time.

In an alternative embodiment (not shown in the drawings), the signalsfrom the control winding are processed digitally. To do this, eachcontrol winding, as opposed to being connected to the other controlwindings, is connected directly to the control unit, which disregardsphases R′, S′, T′ and processes the signals solely as a function of thespatial arrangement of the control windings associated with the transitsignals. More specifically, the control unit is associated with at leasttwo signals of two control windings, and, given two instantaneouspositions, determines speed signal SV and position signal SP.

In this variation, the control unit comprises digital circuits and amicrocontroller.

In another embodiment (not shown), the slide comprises a metal plateinstead of permanent magnets.

In another embodiment of the present disclosure (not shown in thedrawings), the sensors are not embedded in the elongated body, and theelongated body comprises sensor seats.

In another embodiment of the present disclosure (not shown in thedrawings), the sensors are not embedded in the elongated body, and theelongated body has sensor assembly markers.

In this embodiment, both the seats and markers are formed whenmanufacturing the elongated body to minimize noise generated by thepower windings on the sensors.

Though the above description refers specifically to a cabletransportation system, such as a cable-car or chair-lift, the presentdisclosure also extends to any type of transportation system, (e.g., arail transportation system), driven by the actuating described in thepresent disclosure.

Clearly, changes may be made to the system and method as describedherein without, however, departing from the scope of the accompanyingClaims and without diminishing its intended advantages. It should thusbe understood that various changes and modifications to the presentlydisclosed embodiments will be apparent to those skilled in the art andit is therefore intended that such changes and modifications be coveredby the appended claims.

The invention is claimed as follows:
 1. A passenger transportationsystem comprising: at least one rail extending along a path; a trolleymovable along the at least one rail; an actuating device including alinear electric motor having: at least one slide fitted to the trolley,and a linear stator extending at least partly along the path, saidlinear stator including: a body, and a plurality of power windingsembedded in the body; and a plurality of sensors fitted to the body ofthe linear stator, said plurality of sensors including a control windinglocated in relation to the plurality of power windings such that a totalmagnetic flux provided from the power winding associated with thecontrol winding is nil, said plurality of sensors configured to: sense aposition of the trolley, and transmit at least one signal utilized tocontrol the position of the trolley.
 2. The passenger transportationsystem of claim 1, wherein the plurality of power windings include: atleast a first coil wound about a first axis in a first windingdirection, and a second coil wound about a second axis in a second,opposite winding direction, the first coil and the second coil areconnected to each other.
 3. The passenger transportation system of claim1, wherein: the power windings generates a first magnetic field bypassage of current in said power windings, the at least one slideincludes a magnetic field generator configured to generate a secondmagnetic field which interacts with the first magnetic field and causesthe at least one slide to move along the path, the second magnetic fieldtravels through the control winding when the at least one slide travelswithin a designated distance of the control winding, and the controlwinding is configured to generate current by interaction with the secondmagnetic field.
 4. The passenger transportation system of claim 1,wherein: the plurality of power windings include: at least a first coilwound about a first axis in a first winding direction, and a second coilwound about a second axis in a second, opposite winding direction, thefirst coil and the second coil are connected to each other, and thecontrol winding is located at least partly between the first coil andthe second coil to define a region enclosed by the control winding andtraversed by a first magnetic field at the first coil and the secondcoil such that a total magnetic flux of the first magnetic field issubstantially nil.
 5. The passenger transportation system of claim 1,wherein the control winding is coupled to the at least one slide togenerate a transit signal by a varying magnetic flux produced byrelative movement of the at least one slide with respect to the controlwinding.
 6. The passenger transportation system of claim 5, whichincludes a power assembly connected to said power windings andconfigured to power said power windings with electric current having anamplitude, a frequency, and a phase calculated based on the generatedtransit signal.
 7. The passenger transportation system of claim 1, whichincludes a control unit connected to the control winding and configuredto receive a plurality of transit signals and control the power windingsas a function of the received transit signals.
 8. The passengertransportation system of claim 7, wherein the control unit includes acompensating block configured to compensate for any noise in the transitsignals.
 9. The passenger transportation system of claim 1, whichincludes: a draw cable, at least one transportation unit connected tothe trolley and selectively connectable to the draw cable by a couplingdevice, and at least one passenger station where the at least onetransportation unit is disengaged from the draw cable, wherein thelinear stator extends along the at least one passenger station to movethe transportation unit along a portion of said path.